Melt butter in large Dutch Oven over medium high heat. Add squash, potato, pear, salt and pepper to pan; saute 3 minutes. Add leek; saute 1 minute. Stir in broth; bring to a boil. Reduce heat, and simmer about 20 minutes or until potato is tender, stirring occasionally, Place half of the mixture in the blender. (REMOVE CENTER PIECE OF LID TO ALLOW STEAM TO ESCAPE). Secure lid on blender and place towel over opening to avoid splatters. Blend until smooth. Pour into a larger bowl and repeat procedure until remaining soup is complete. Stir in half and half. Cover and serve warm.